One vertex per element, one color per generator, with an edge from x to x·s.
(5,6)(7,11)(8,12)(9,10)(13,14,19,25)(15,23,16,21)(17,22,27,28)(18,26,20,24)(1,2)(3,4)(6,10)(11,12)(13,15,19,16)(14,21,25,23)(17,18,27,20)(22,24,28,26)(5,7,9,8)(6,11,10,12)(13,16,20,17,19,15,18,27)(14,22,26,21,25,28,24,23)(2,4)(5,8,9,7)(6,12,10,11)(13,17,20,15,19,27,18,16)(14,23,26,22,25,21,24,28)(6,10)(11,12)(13,18,19,20)(14,24,25,26)(15,27,16,17)(21,28,23,22)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.